Theoretical Study for Practical Applications of Information Theoretically Secure Cryptosystems

我们从理论上研究了信息安全密码体制，以使其更具实用性。因此，沿着这一研究方向，我们得到了三个结果。主要结果是：(1)给出了(2，2)-门限秘密共享方案的防欺诈编码定理；(2)放松了信息理论安全概念，提出了一种高效的可视秘密共享方案；(3)重新审视了信息理论安全与计算安全的对称密钥加密之间的关系。此外，我们还在密码学和信息安全方面取得了一些结果，有效地利用了信息论方法。

We studied information theoretically secure cryptosystems in order to make them more practical. As a result, we obtained three results along with this research direction. Three main results are : (1) coding theorems for (2,2)-threshold secret sharing schemes secure against cheaters, (2) a proposal of efficient visual secret sharing schemes by relaxing information theoretical security notion, and (3) a new look at relations among information theoretically secure and computationally secure symmetric key encryptions. Furthermore, we obtained several results in cryptography and information security in which information theoretic methods are effectively utilized.